%N Number of terms in longest arithmetic progression of consecutive primes starting at n-th prime (conjectured to be unbounded).

%C a(n) <= 4 for n <= 10^5. - _Reinhard Zumkeller_, Feb 02 2007

%C The first instance of 4 consecutive primes in an arithmetic progression is (251, 257, 263, 269), which starts with the 54th prime. The first instance of 5 consecutive primes in an arithmetic progression is (9843019, 9843049, 9843079, 9843109, 9843139), which starts with the 654926th prime. [_Harvey P. Dale_, Jul 13 2011]